The present invention relates to track systems for vehicles and, in particular, a switching system for individually and selectively routing vehicles between a main track and merged tracks on a dedicated route.
Dedicated railed routing systems have been proposed for coordinating travel of vehicles along tracked paths. Frequently proposed systems include monorails, fixed rails, magnetic levitation systems and the like wherein all vehicles travel in synchrony along a main transit path and are merged thereto and therefrom for mass or individual entry or egress. One of the significant problems encountered in such approaches in maintaining traffic flow under merging conditions. Inasmuch as it is beneficial to maintain the traveling vehicles in close array for optimum traffic density and speed, safe and efficient entry and exit is of prime importance. Heretofore, it has been necessary to alter traffic flow on the main path to permit the discrete vehicle to enter or leave. This has required slowing traffic speeds at such points and providing sufficient vehicle spacing to permit the safe routing of the intended vehicle without inadvertently effecting proximate vehicles. Moreover during such traffic handling it is important that the routed vehicle remain stable under affirmative steering control.
For example, U.S. Pat. No. 889,441 to Christopher discloses a railway switch wherein a tracked vehicle selectively engages a ramp in advance of a turn off to shift mechanically track tongues to a position prescribing a divergent path. Such mechanical mechanism is slow acting and must be mechanically returned to the original position to avoid inadvertently affecting following traffic.
U.S. Pat. No. 3,363,584 to Brush et al. discloses a vehicle control system wherein one side of the vehicle is controlled by a rail system for main traffic routing and the opposed side of the vehicle is controlled by a second rail system to route the vehicle for egress and entry. Control requires alternative selective shifting for engaging the desired path and disengaging the prior path.
U.S. Pat. No. 3,451,351 to Hawes discloses a monorail switching system wherein laterally spaced guide rollers are selectively deployed to transfer steering and routing control between a main path and a transfer path. A similar system is disclosed in U.S. Pat. No. 3,593,668 to Adams wherein selectively lowered guide wheels are switched prior to a junction between a main channel and a transfer channel for electively steering a tracked vehicle at a transfer point.
U.S. Pat. No. 3,595,173 to Giraud discloses a roof plate on a vehicle that is raised to selectively engage a merging ramp for vertically routing a vehicle at a transfer junction.
U.S. Pat. No. 3,628,462 to hit discloses a vehicle switching apparatus wherein pivoting rollers on the vehicle are alternatively deployed for switching between a main path and a transfer path.
U.S. Pat. No. 3,640,227 to Webb discloses a suspended rail car system wherein swinging support rollers are selectively deployed between a main path and a divergent path for controlling the course of the car.
U.S. Pat. No. 3,838,648 to Dahlberg et al. discloses a transportation system wherein the vehicle selectively traverses ramped surfaces a divergent transfer points.
U.S. Pat. No. 4,092,931 to Wulf et al. discloses a guide mechanism for vehicles wherein steering control on a fixed path is provided by longitudinally spaced guide wheels engage a guide channel for controlled routing of the vehicle.
U.S. Pat. No. 5,016,542 to Mitchell discloses a transit system wherein hydraulically operated vanes are selectively deployed for routing a vehicle between a main line and a station.
The foregoing, while providing merging capabilities, require excessive vehicle separation in operation. Additionally, the systems do not provide for affirmative directional control of the vehicle during such maneuvers. Further, many of the systems do not readily adapt to incorporation with passenger vehicles in high speed applications requiring stable steering control during merging conditions.
In view of the above limitations, it is an object of the present invention to provide a switching system for tracked vehicles that is selectively deployed for entering tracked transit and for accessing merging conditions.
Another object of the invention is to provide a steering system for transit vehicles that retain affirmative tracking control during non-linear movement.
A further object of the invention is to provide a keel assembly for a transit vehicle that is selectively engagable with a track system for steering the vehicle during travel and merger conditions with minimum spacing between vehicles.
Yet another object of the invention is to provide a tracking system for vehicles that is selectively engaged by a steering keel deployed from the vehicle for affirmatively prescribing travel and merger operation.
The foregoing objects are accomplished by a monorail switching system for guided vehicles having a main guideway mounted below the transportation monorail that is selectively engaged a vertically shiftable elongated keel assembly deployed by the vehicle. For entrance/exit junctions, a secondary guideway below the main guideways defines the junction path and may be selectively engaged by lowering the keel assembly at a joint transition zone prior to the transfer route. The plural guideways permit vehicles to travel in concert notwithstanding selective revision at the junctions.